URI::RFC2396_Parser#escape

# File tmp/rubies/ruby-3.2.0/lib/uri/rfc2396_parser.rb, line 287
def escape(str, unsafe = @regexp[:UNSAFE])
  unless unsafe.kind_of?(Regexp)
    # perhaps unsafe is String object
    unsafe = Regexp.new("[#{Regexp.quote(unsafe)}]", false)
  end
  str.gsub(unsafe) do
    us = $&
    tmp = ''
    us.each_byte do |uc|
      tmp << sprintf('%%%02X', uc)
    end
    tmp
  end.force_encoding(Encoding::US_ASCII)
end